1. Field of the of the Invention
The present invention relates to a beam or girder joint element for joining or fastening a beam or girder to a column.
2. Prior Art
There has been proposed such a beam or girder joint element as shown in FIG. 15, which is formed by a plate member 1 of a T-shaped cross-section. The plate member 1, which is made of metal, is composed of a square column connecting plate portion 2 and a square beam or girder connecting plate portion 4 extending therefrom perpendicularly thereto. The column connecting plate portion 2 has a length W.sub.2 in the lateral direction, a length H.sub.2 in the vertical direction and a thickness D.sub.2 ; the plate portion 2 has, for example, four bolt holes 3. The beam or girder connecting plate portion 4 has a length W.sub.4 in the lateral direction, a length H.sub.4 equal to that H.sub.2 of the plate portion 2 in the vertical direction and a thickness D.sub.4 ; the plate portion 4 has, for example, two bolt holes 5. Reference numerals 2a and 2b denote front and rear surfaces of the column connecting plate portion 2.
In this case, the four bolt holes 3 of the column connecting plate portion 2 are arranged in pairs one above the other in right and left halves of the plate portion 2, and the two bolt holes 5 of the beam or girder connecting plate portion 4 are also arranged one above the other.
As described below with reference to FIGS. 16 and 17, it is possible, with such a conventional beam or girder joint element, to fasten or join a girder or beam 20 to a column 10 by means of bolts 31, nuts 32 and washers 33 and bolts 41, nuts 42 and washers 43.
The column 10, which is normally made of wood, is square in cross-section; left- and right-hand sides 10L and 10R of the column 10 each have a width W.sub.10 substantially equal to or larger than the length W.sub.2 of the column connecting plate portion 2 of the plate member 1 forming the beam or girder joint element. The column 10 has four bolt holes 13 which extend between the left- and right-hand sides 10L and 10R, corresponding to the four bolt holes 3 of the column connecting plate portion 2, respectively. Furthermore, the column 10 has a clearance groove 12 cut in its right-hand side 10R so that the column connecting plate portion 2 of the plate member 1, the tips of the bolts 31 and their nuts 32 and washers 33 do not protrude from the right-hand side 10R when the plate member 1 is attached to the column 10 as described later.
The beam or girder 20, which is also normally made of wood, has a left-hand end face 20LF corresponding to the right-hand side 10R of the column 10 and is square in cross-section. The beam or girder 20 has a groove 24 which has a width D.sub.24 nearly equal to the thickness D4 of the beam or girder connecting plate portion 4 of the plate member 1 and a length L.sub.24 nearly equal to or slightly larger than the length W.sub.4 of the plate portion 4 and which extends vertically between the top 20U and bottom 20D of the beam or girder 20 and extends laterally to the left-hand end face 20LE. Furthermore, the beam or girder 20 has to bolt holes 25 which are nearly equal in diameter to the bolt holes 5 of the beam or girder connecting plate portion 4 of the plate member 1 and extend between the front 20F and back 20B of the beam or girder 20 across the above-mentioned groove 24.
The bolts 31 are headed ones corresponding to the bolt holes 3 of the column connecting plate portion 2 of the plate member 1 and the bolt holes 13 of the column 10, and the nuts 32 are hexagonal.
The bolts 41 are also headed ones corresponding to the bolt holes 5 of the beam or girder connecting plate portion 2 of the plate member 1 and the bolt holes 25 of the beam or girder 20, and nuts 42 are hexagonal.
The beam or girder 20 is fastened or joined to the column 10 by means of the bolts 31 and their nuts 32 and washers 33 and the bolts 41 and their nuts 42 and washers 43 in such a fashion as described below.
At first, the plate member 1, which forms the beam or girder joint element, is held against the right-hand side 10R of the column 10 with the column connecting plate portion 2 received in the clearance groove 12 of the column 10, then the bolts 31 with the washers 33 put thereon are inserted through the bolt holes 13 of the column 10 from the left-hand side 10L thereof, then the remaining washers 33 are put on the free ends of the bolts 31, and the nuts 32 are thread-mounted on the projecting ends of the bolts 31 and tightened toward the column 10. In this way, the plate member 1 is fastened to the column 10.
Next, the beam or girder 20 is held against the right-hand side of the column 10, with the groove 24 receiving the beam or girder connecting plate portion 4 of the plate member 1 and the left-hand end face 20LE abutting against the right-hand side 10R of the column 10, then the bolts 41 with the washers 43 put thereon are inserted through the bolt holes 25 of the beam or girder 20 across the bolt holes 5 of the beam or girder connecting plate portion 4 of the plate member 1, then the remaining washers 44 are put on the free ends of the bolts 41 and the nuts 42 are thread-mounted on the projecting ends of the bolts 41 and tightened to the beam or girder 20. In this way, the beam or girder 20 is fixed to the beam or girder connecting plate portion 4 of the plate member 1 and consequently to the column 10.
As described above, it is possible, with the conventional beam or girder joint element of FIG. 15, to secure the beam or girder 20 to a desired side of the column 10 (the right-hand side 10R in the above).
However, the conventional beam or girder joint element cannot firmly be fixed to the column 10 because the column connecting plate portion 2 of the plate member 1 is secured by the bolts 31 alone.
The conventional beam or girder joint element calls for the provision of the clearance groove 12 in the desired side of the column 10 so that the column connecting plate portion 2 of the plate member 1, the free end portions of the bolts 31 and their nuts 32 and washers 33 do not protrude from the side surface of the column 10 when the plate member 1 is fixed thereto. The clearance groove 12 needs to be large and deep enough to receive the column connecting plate portion 2 of the plate member 1--this naturally reduces the strength of the column 10.
The conventional beam or girder joint element has another defect that the beam or girder 20 must be supported from below when inserting the bolts 41 through the bolt holes 25 of the beam or girder connecting plate portion 4 of the plate member 1 and thread-mounting the nuts 42 on the free ends of the bolts 41 while holding the left-hand end face 20LE of the beam or girder 20 against the specified side of the column 10 after fixing the plate member 1 thereto--this is very cumbersome.